钢索上采用瓷瓶吊装绝缘导线布线时，支持点间距不应大于1.5m。线间距离在屋外不应小于50mm。( )
参考答案：错
My English teacher had a trip to the USA last summer. Which picture did she take there? [ ]
A. B. C. D.
母亲与胎儿通过下列哪个结构进行物质和气体交换（ ）
A．胎盘和脐带
B．子宫内膜
C．输卵管
D．卵黄
B.
C.
D.